Antihalation film



May 15,1945; 'e. F. NADEAU ANTIHALATION FILM Filed Jan. 14. 1943 2 Sheets-Sheet 1 FIG. 2

IoZoJO IOO.

% PHTHALYL INVENTOR.

685 M QM VATTORNEYS GALE .FZ MDEAU" May 15, 1945-. G. F. NADEAU I ANTIHALAT IO FILM v 2 Sheets-Sheet 2 Filed Jang 14, 1943 60 70 I so .90 100 L IO 20 30 4O PHTHA FIG HALATIQON LAYER 0F A H VISCOSITY CELL UL05E ACYL PHTHALATE,CARRYING A DYE 7% PHTHALYL GALE F. NADEAU INVENTOR BY W W 2e M 0 I0 2 Patented May 15 1945 Gale F. Nadeau, Rochester, N. Y assignor-to Eastman Kodak Company, Rochester, N. Y., a corporation of New Jersey Application January 14, 1943, Serial No. 472,342

- 4 Claims. (Cl. 95-9) This invention relates to photographic film, and more particularly to film provided with antihalation layers.

Antihalation backing layers of the type having a light-absorbing materialdispersed in a vehicle soluble in alkaline photographic processing solutions are well known. Less well known are antihalation layers of the type insoluble in processing solutions. Such layers have a light-absorbing material, generally a dye solubl in or decolorizable by processing solutions, dispersed in a colloidal material insoluble in but permeable to the processing solutions. It is antihalation layers of the latter type which are described in the present invention and which are herein termed non-removable antihalation layers. I

Antihalation layers of this type are especially useful for types of film which must be wound into tight rolls without interleaving paper. In this case it is apparent that the emulsion of one section of the film would be in intimate contactwith the antihalation layer of another section of the film and, therefore, if there is any tendency for the dye of the antihalation layer to transfer,

' the emulsion may become stained. Antihalation layers of gelatin or other similar moisture susceptible materials are especially bad in this respect. The antihalation layers of the present invention are advantageous since antihalation dyes do not readily transfer from them to adjacent surfaces.

In the Nadeau and Slack U. S. Patent 2,311,073, granted February 16, 1943, and Nadeau and Slack, p. S.- Patent 2,326,056, granted August 3, 1943, are described non-removable antihalation layers consisting of aliphatic monobasic organic aciddicarboxylic acid esters of cellulose containing substantially 4 to 8 aliphatic monobasic organic acid acyl and dicarboxylic acid acyl groups per Cu cellulose unit, of which not more than one is a dicarboxylic acid acyl group and'the remainder are aliphatic monobasic acid acyl groups of less than five carbon. atoms. As explained therein, cellulose esters of this type are not suitablefor non-removable antihalation layers if they contain more than that proportion of dicarboxylic acid acyl groups (more than about 15 to 16 per cent dicarboxylic acid acyl) since they are soluble in photographic processing solutions.

I'have found that if cellulose esters of this type have a sufiiciently high viscosity and a certain proportion of monobasic acid acyl groups, the proportion of dicarboxylic acid acyl groups may be substantially increased without the ester non-removable antihalation backing layers. They show little tendency for the antihalation dye to bleed or transfer from the layer and since they have high carboxyl content, they are capable of retaining more dye in the layer than the esters previously described. This is particularly. true when the antihalation dye is a basic dye. Also, these esters are more soluble in coating solutions and are more compatible with film supports than esters previously described.

One object of the present invention is to provide cellulose monobasic organic acid-dicarboxylic acid esters having a relatively large proportion of dicarboxylic acid acyl groups but which by virtue of certain viscosities and monobasic acid acyl contents, are suitable for use in non-removable antihalation layers.

Another object is to provide a method of apply- 2 ing the cellulose esters to photographic films as the vehicle for non-removable antihalation layers. Other objects will appear from the following description.

The objects of the present invention 'area'ccomplished by using for antihalation layers, cellulose esters having compositions lying within areas EFG, BEFG and .EFGH-of the'attacheddrawings and having a viscosity such that the layer is permeable to, but insoluble in, water and alkaline photographic processing solutions, said layer carrying a light-absorbing dye.

.In the accompanying drawings, Figs. 1-4 show ferring to Fig. 1, the cellulose formate phthalates contemplated have compositions falling within area EFG. The lines which delimit this area connect points E, F, and G, which have formyl contents of about 29, 23, and 16 per cent respectively, and phthalyl contents of 14, 26, and 16 per cent .respectively. In the same figure area ABCD represents cellulose formate phthalates of the composition described in the cited prior art. Similarly, in Fig. 2 the compositions of the cellulose acetate phthalates of the invention lie within area EFG, the esters represented by points E, F, and G, having acetyl contents of about 38,

27, and 16 per cent respectively, and phthalyl contents of about 11, 30, and 16 per cent-respectively. Area ABCD of this figure contains cellulose acetate phthalates of the composition described in the cited prior art.

In Fig. 3 are shown the compositions of the cellulose propionate phthalates of the invention, those esters of composition lying within area EFGH, points E, F, G, and H representing esters cent respectively, and phthalyl contents of about 11, 15, 35,- and lfi'per cent respectively. Area ABCD of this figure contains cellulose butyr'ate phthalates of the composition described in the prior art cited.

In addition, my invention contemplates cellulose esters of at least two lower aliphatic monobasic acids and phthalic acid, for example, cellu lose formate acetate-, formate propionate-, formate butyrate-, acetate propionate, acetate butyrate-', propionate butyrate-phthalates, etc.,-,of compositions which may be seen by considerationof Figs. 1-4 of the drawings. Taking for example, the .case of cellulose acetate propionate phthalates; the composition of these esters lies intermediate between the bounds of area EFG of Fig. 2 and area EFGH of Fig. 3, that is, according to area EFG of Fig. 2 a given ester can have no more than about 33 per cent acetyl (point E) .but from area EFGH of Fig. 3 it is seen that the ester may have propionyl groups replacing acetyl groups in the molecule, the ratios of the propionyl to acetyl groups of these esters being obtamed by extrapolation. As examples of such esters are given, cellulose acetate propionate phthalate (15% acetyl, propionyl and 19% phthalyl) and cellulose acetate butyrate phthalate (17% acetyl, 12% butyryl and 18% phthalyl). The extrapolation is made with the prerequisite in mind that the total number of monobasic acid and dibasic acid acyl groups per cellulose unit can be no greater than that of the simple esters of composition shown in Figs. 1-4.

In this specification and in the appended claims where it is stated that the acyl phthalate esters of the invention have compositions lying within areas EFG, BEFG, and EFGH, of the figures of the drawings, it is to be understood that this includes not only those esters whose compositions can be read directly fromwithin the limits of these areas but also those esters of at least two monobasic acids and phthalic acid whose compositions are determined by extrapolation within the limits of said areas.

In addition to having compositions lying within the mentioned areas of the drawings the esters have a viscosity of the order of 50 to 300cmacyl content (to the left of the areas) are too impermeable to aqueous solutions to be of use in.

non-removable antihalation layers. Esters of compositions lying below or to the right of these areas contain a large proportion of carboxyl groups, and since they tend to be soluble in alkaline processing solutions, they are not of use in non-removable antihalation layers. It is, therefore, apparent that in addition to viscosity the proportion and size of the monobasic acid acyl group or groups in the cellulose ester molecule plays an important part in determining the solubility.

As mentioned previously, the cellulose esters described in the above'Nadeau et a1. applications have compositions falling within regions ABCD of Figs. 1-4 and their viscosities are of the order of 4 to 5 centipoises measured as above described. Esters of this range of viscosity must contain less than about one dicarboxylic acid acyl group per C24 cellulose units if they are to be insoluble in alkaline photographic processing solutions, whereas the esters of the present invention contain more than one dicarboxylic acid-acyl group per C24 cellulose unit.

The cellulose esters contemplated by my invention may be prepared by the method described in drawings. As shown. in Fig. 5, 1r yer i0 is a cellutipoises. This viscosity is determined at25 C. on r a 10 per cent solution of the ester .in a mixture .of 55 parts of 95 per cent ethyl alcohol and 45 the Malm and Waring U. S. Patent 2,093,462,

carrying an antihalation layer of a cellulose ester of the invention will now be described with particular reference to Fig. 5 of the accompanying lose ester film support carrying on one side thereof a light-sensitive emulsion layer l3 adhesively joined to the support 10 by means of the subbing layer 12 which may be gelatin'or other suitable material. On the opposite side of the support is the antihalation layer ll of the invention consisting of a high viscosity cellulose ester selected from those having, compositions lying within areas EFG, BEFG, and EFGH, of thedrawings. A film so constructed may be provided with the antihalation layer of the invention in the following manner.

A photographic film support of a cellulose organic or inorganic acid ester for example such as cellulose acetate, and already provided with a light-sensitive emulsion layer if desired, is coated on the support side with ,a solution of cellulose acetate phthalate (24% phthalyl, 27.6% acetyl and 107 cps; viscosity or 20.6% phthalyl, 30.6% acetyl and 306 cps. viscosity), from the'followin This coating is dyed by means of a solution of a suitable dye, for example, of the fugitive-type from a solution of the following typical composition:

i p 1 Per cent A dye -1 2.5 "B dye 1.5

Aeoroso1 AY (sodium sulfo diamyl succinate) Ethyl alcohol 25 Methyl'alcohol 70 Typical dyes useful in the above formula and designated as A and B dyes are fugitive dyes h ving compositions lying in regions of higher such as Acid Magenta (800), Acid Greenxfloe),

j 2,378,175 I Acid Blue3R (sulfonated triphenyl methane dye) and suiionated Malachite Green (Muehler U. S. Patent 2,150,695, granted'March 14, 1939). The numbers'following the names of the dyes refer to the Schultz Dyestufi Tables, 7th edition, 1931. These dyes are fugitive dyes of the acid type and are bleachable in photographic processing solutions. If desired the dye may be coated as an amine salt as described in Nadeau et al., U. S. Patent 2,326,057, granted August 3, 1943.

In order to aid in the prevention of diffusion of the dye in the backing layer, a layer of cellulose ester such as cellulose acetate 'phthalate may be coated over the the antihalation layer using solutions essentially inactive toward the dye and the vehicle of the antihalation layer as, for example, a 1.5 per cent solution of water permeable cellulose acetate phthalate in ethyl acetate. If

desired, this coating may be applied from a mixture of 85 parts of ethyl acetate and parts of alcohol or butyl acetate may be used. This process of coating in antihalation layer with a proat al. U. S. patent application, Serial No. 420,088,

filed November 22, 1941, and the materials described'therein and in the present invention are which comprises a support provided with a light.

sensitive emulsion layer and an antihalatlon layer of a cellulose prcpionate phthalate selected from those having compositions lying within area EFGH of Fig. 3 of the attached drawings and hav ing a viscosity of at least about 56 centipoises when measured at 25 C. in a 10% solution of the cellulose propionate phthalate in a mixture of 55 parts of 95% ethyl alcohol and i5 parts of acetone, said layer carrying a light-absorbing dye. v I

'3. Aphotographic element free from halation which comprises a support provided with a light sensitive emulsion layer and an antihalation layor of a cellulose acyl phthalate selected from those compositions of cellulose formate phthalate lying within area EEG of Fig. 1 of the drawings,

itective layer is described more fully in the Nadeau suitable for this purpose. The choice of solvents 7 for coating the protective layer is simplified if may carry a plurality of uncolored or" colored ,emulsion layer sensitive to different regions of the spectrum such as are suitable for color films processed by well-known methods of color-forming development or in a process where dyes are bleached out under influence of a silver image.

It is to be understood that the disclosure herein is by way of example, and that I consider as in- ;cluded in my invention all modifications and equivalents falling within the scope of the appended claims. g i

What I claim is: 1. A photographic element free from halation which comprises a'support provided with alightsensitive emulsion layer and an antihalation layer of a. cellulose acetate phthnlate selected from those having compositions lying within area EFG 01' Fig. 2 or the attached drawings and havinga viscosity of at least about 50- centipoises when measured at 25 C. in-a 10% solution of the cellu-.

lose acetate phthalate in amixture of 55. parts of 95% ethyl alcohol and '45 parts of acetone, said layer carrying a light-absorbing dye.

2. A photographic element tree from halati cellulose acetate phthalate lying within area EFG of Fig. 2 of the drawings, cellulose propionate phthalate lying within area EFGH of Fig. 3 of the drawings, cellulose butyrate phthalate lying within area BEFG of Fig. 4 of the drawings, and

mixed cellulose esters containing at least two monobasic aliphatic acid acyl groups of less than live carbon atoms and a phthalyl group having a composition lying intermediate between the bounds of two of said areas of Figs. 1 to a, the ratios of the difierent types of monobssic acid acyl groups being obtained by extrapolation with the prerequisite that the total number of monobasic acid and dibasi'c acid acyl groups per cellulose unit cah be no greater than that of the simple esters of composition represented by those Figs. 1 to 4 between which the extrapolationis made, and having a viscosity of at least-about 50 centipoises when measured at 25 C. in a 10% solution of the cellulose acyl phthalate in a mixture of 55 parts of ethyl alcohol and 45 parts of acetone, said antiha'lation layer having a lightabsorbing dye therein.

4. A photographic element free from halation,

which comprises a support provided with alishtsensitive. layer and an antihalation' layer of'a mixed cellulose ester containing at least two,

monobasic aliphatic acid a'oyl groups of less than five carbon atoms-and a phthalyl group selected from those esters, having a composition lying in termediate between the bounds of two of the. areas EFG of Figs 1 of the drawings; EFG of Fig. 2, and EFGH of Fig. 3 01' the drawings, and BEFG of Fig. 4 or the drawings, the ratios of the diflerent types or 'monobasic acid acyl groups being obtained by extrapolation with the prerequisite that the total number or monobasic acid and dibasic acid acyl groups per cellulose unit can be no greater than that of the simple esters of composition represented by those Figs. 1 to d between which the extrapolation is made and havinga'viscomty' of at least about 50 centipoises when measured at25 C. in a 10% solution otthe cellulose'acyl phthalate in admixtureor 55 parts 010575 ethyl alcohol and 45 parts of acetone, said'antihalation layer having a light-absorbing dye therein.

GAL-h 1". NADEAU. 

